TRILL (Transparent Interconnection of Lots of Links) is an L2 network standard recommended by the IETF. A TRILL network includes Routing Bridge (RB) devices supporting the TRILL protocol, where multi-destination packet (including unknown unicast packet, multicast packet and broadcast packet) in the TRILL network are forwarded by using a multicast tree, and the respective RB devices calculate multicast forwarding entries of the multicast tree, and forward the multi-destination packet according to the multicast forwarding entries. If there is a change in topology in the TRILL network, for example, some link in the network fails, then the failure can be detected by an RB device connected with the failing link, and synchronized to the other RB devices in an LSP (Link State Protocol data unit). The respective RB devices need to update topology information and recalculate the multicast forwarding entries.